Université de Paris, IAME, INSERM, Paris, France.
Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France.
Elife. 2021 Sep 27;10:e69302. doi: 10.7554/eLife.69302.
The relationship between SARS-CoV-2 viral load and infectiousness is poorly known. Using data from a cohort of cases and high-risk contacts, we reconstructed viral load at the time of contact and inferred the probability of infection. The effect of viral load was larger in household contacts than in non-household contacts, with a transmission probability as large as 48% when the viral load was greater than 10 copies per mL. The transmission probability peaked at symptom onset, with a mean probability of transmission of 29%, with large individual variations. The model also projects the effects of variants on disease transmission. Based on the current knowledge that viral load is increased by two- to eightfold with variants of concern and assuming no changes in the pattern of contacts across variants, the model predicts that larger viral load levels could lead to a relative increase in the probability of transmission of 24% to 58% in household contacts, and of 15% to 39% in non-household contacts.
SARS-CoV-2 病毒载量与传染性之间的关系尚不清楚。本研究利用病例和高危接触者队列数据，重建了接触时的病毒载量，并推断了感染的概率。病毒载量对家庭接触者的影响大于非家庭接触者，当病毒载量大于 10 拷贝/毫升时，传播概率高达 48%。传播概率在症状出现时达到峰值，平均传播概率为 29%，个体差异较大。该模型还预测了变异对疾病传播的影响。基于目前的知识，即病毒载量会因关注的变异而增加 2 至 8 倍，并且假设不同变异的接触模式没有变化，该模型预测，更大的病毒载量水平可能导致家庭接触者的传播概率相对增加 24%至 58%，非家庭接触者的传播概率相对增加 15%至 39%。
